Screen spline with direct frictional engagement means



Aug. 4, 1959 G. KESSLER 2,897,889

SCREEN SPLINE WITH DIRECT FRICTIONAL ENGAGEMENT MEANS Filed May 27, 1957GERALD KESSLER INVENTOR ATTORNEY United States Patent SCREEN SPLINE WITHDIRECT FRICTIONAL ENGAGEMENT NIEANS Gerald Kessler, Youngstown, OhioApplication May 27, 1957, Serial No. 661,671

5 Claims. (Cl. 160-392) This invention relates to an improved screenspline of plastic or similar resilient material, of the type which isforced into a groove in a metal, plastic or wood screen frame in orderto retain and attach screen material by frictional engagement in saidgroove.

It is known practice to fasten screening such as insect screening forwindows to the screen frame by providing a groove around the frame intowhich the screening is forced by means of a resilient elongated splinemember which frictionally retains the screening in the groove. Theresilient spline member is, according to known practice, a rod or tubeusually of plastic or similarly resilient material, sometimes providedwith axially extending radial I with such an arrangement to providesufficient friction to satisfactorily retain the screen material inplace in the frame, particularly with the increasingly popular use ofmetal framing such as extruded aluminum, and metal or plastic screenmaterial, which provides a rather low coefiicient of friction in contactwith the aluminum.

According to the invention, a spline member is provided in anarrangement such as is described above, wherein there are a number ofprotuberances on. the surface of the spline in the form of spurs orknobs, these being of sulficiently small dimensions to pass through theapertures in the screen which is being retained into direct engagementwith the walls of the groove. This spline is preferably made of aresilient plastic material having a much higher coeflicient of frictionin engagement with the walls of the groove than does the screenmaterial. Furthermore, the small spurs or knobs protruding through thescreening material into contact with the frame provide a Wedging actionwhich also tends to maintain the screen material firmly positioned inthe groove.

It is accordingly a primary object of the invention to provide animproved spline construction for retaining screen material by means of agroove formed in a rigid supporting member to which the screening is tobe attached.

The specific nature of my invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings, in which:

Fig. 1 is a partly sectional perspective view of a portion of anordinary window screen showing the manner of attaching the screenmaterial to the frame;

Fig. 2 is a sectional view of a screen similar to Fig. l and on anenlarged scale, showing the use of a screen spline according to theinvention;

Fig. 3 is a schematic perspective view of a strip of conventionalplastic spline material;

2,897,889 Patented Aug. 4, 1959 Fig. 4 is a sectional view taken on line4-4 of Fig. 5 of one form of spline made according to the invention;

Fig. 5 is a sectional view taken on line 55 of Fig. 4;

Fig. 6 is a sectional view taken on line 66 of Fig. 7, showing anotherform of spline according to the invention;

Fig. 7 is a sectional view taken on line 77 of Fig. 6;

Fig. 8 is a sectional view showing a corrugated groove; and

Fig. 9 is a sectional view showing another form of groove.

A typical application of the invention would be to a conventional windowscreen, as indicated in Fig. 1, wherein the frame 2 is provided with agroove 3 for receiving the screen material 4, which is held in place bya spline 6. In this type of known construction, considerable difficultyhas been experienced, particularly since the advent of aluminum framing,in securing sufficient frictional contact between the screen 4 and thewalls of groove 3 to retain the screen firmly in place. The screenmaterial may be made of aluminum or copper wire mesh, or of suitableplastic material, but in all cases, the commercially available screeninghas a relatively hard glossy surface which has a rather low coeflicientof friction in contact with the hard surface walls of the aluminumframing. One way of improving this situation is to provide extrudedparallel corrugations in the walls of the channel as shown at 13 in Fig.8. This may be helpful in some cases, but if the corrugations are madetoo sharp, they tend to tear the screen material, while if they are notmade very sharp, the frictional engagement between the relatively hardsurfaces of the framing and the screening materials will still not besutlicient for the purpose.

One form of spline material now widely used is shown at 6a in Fig. 3,wherein the spline consists of a tubular extrusion plastic material, theexterior surface of which is axially serrated. In practice, theseserrations tend to engage the adjacent surface of the screening as shownin Fig. l, but the basic frictional engagement of the screen material 4with the walls of the groove 3 is not thereby improved, and theditficnlty still exists.

Figs. 4 and 5 show at 6b one modification of splining according to theinvention, wherein the spline member, of extruded plastic material, isprovided with a plurality of knobs or protuberances 7 extendingoutwardly from its surface for a suflicient distance to penetratethrough the pores 01 apertures of the screen material as shown in Fig. 2and engage directly the walls of groove 3. The physical characteristicsof the plastic material of which the spline is made can, of course, becontrolled to a considerable extent in production, and are deliberatelyselected so as to provide a much greater coefiicient of friction than isprovided by the screen material. In this Way, the use of the improvedspline construction and material shown provides the necessary frictionalengagement to insure that the screen material will not be easilydisplaced from the groove. In addition to the frictional effect, thetiny fingers 7 protruding through the screen mesh also tend to lock bywedging action between the screen material and the wall of the frame,thus providing further assurance against displacement of the screenmaterial. It will be understood that the average diameter of the knobs 7is sutficiently small to pass through the apertures in the screenmaterial with which it is to be used.

A typical form of construction is shown in Figs. 2 and 9 at 5 and 5respectively, wherein an overhanging lip is formed in the channelinterlocking with the screen material due to the pressure of therelatively elastic spline material forcing the screening under the lip5. However, with the use of my improved spline, the knobs 3 7 passthrough the screen apertures and some of them will lock under the lip asshown at 7' so that it is difficult to remove the screen by pulling onit without shearing offthe knobs 7 which are thus locked. Similarly, oneor more ribs may be provided in the sides of the channel as shown at 13in Fig. 8, and at 15 in Fig. 9, to provide still more locking action ofthe same type. It will thus be apparent that an actual mechanicallocking action is provided which resists pulling out of the screen to amuch greater degree than is otherwise possible. In addition to theoverhanging lip 5 or 5', there may also be provided, as shown at in Fig.9, one or more ridges in the side wall of the channel, with which theprotuberances 7 will still further engage to provide locking action verysimilar to that previously described. 1

Figs. 6 and 7 show another and preferred manner of making the spline. Inthis case the spline 6c is extruded with a plurality of radiallyoutwardly extending fins 8, each of which provides a continuouslongitudinally extending fin, and which 'is therefore not suited forapplicants purpose in this form. However, each fin 8 can be cut into aplurality of individual small knobs suitable for applicants purpose, itbeing necessary only to make the individual protruding pieces of the finsmall enough to pass through the holes in the screen. This can be donein any suitable manner, by cutting each fin into a number of smallpieces, each attached only at its base to the spline member. Forexample, a spiral cut can be made in the fins, similar to the cutting ofa thread in a machine screw, the adjacent turns of the spiral beingspaced sufliciently close together so that each fin 8 is cut into aseries of individual protuberances 8a as shown in Fig. 7, each of whichis sufficiently small to pass through the apertures of the screenmaterial with which it is to be used. In this way, a spline is simplyand economically formed which has a very large number of smallprojections and which insures that a sufiicient number of projectionswill pass through the apertures of the screen to provide the frictionalengagement and locking action above described.

It will be apparent that the protuberances on the spline may be providedin any of a large number of different ways, the essential feature beingthat a multiplicity of protuberances is provided sufiiciently small indiameter to pass through the apertures of the screen material, ofsufficient length to engage the Walls of the channel in which the screenmaterial is retained, and having a sufficiently great rigidity and highcoefficient of friction in contact with the screen material for theintended purpose.

It will be apparent that the embodiments shown are only exemplary andthat various modifications can be made in construction and arrangementwithin the scope of my invention as defined in the appended claims.

I claim:

1. In combination, a screen having apertures, a frame member having alongitudinal channel in the face thereof, and means for fastening saidscreen in said channel comprising an elongated resilient plastic splinemember of uniform composition, said spline member being slightly thickerin cross-section than the Width of said channel and having a pluralityof plastic spike-like protuberances of the same uniform composition asthe rest of the spline member extending outwardly from its surface, thecrosssection of each said protuberance being sufficiently small to passfreely through the apertures of the screen into frictional contact withthe Walls of said channel.

2. The invention according to claim 1, said protuberances extendinglongitudinally in a series of rows, each said row constituting a finextending from the surface of said spline, each said fin comprising anumber of adjacent aligned protuberances substantially contiguous toeach other at a surface of contacts, the surfaces of contact of adjacentrows being slightly displaced to form a helical pattern on said spline.

3. The invention according to claim 1, said channel having a lip on anupper edge thereof extending into the channel, whereby someprotuberances on said spline member extend through said screen againstthe underside of said lip to provide a positive locking action againstdisplacement of said screen.

4. The invention according to claim 1, said channel having at least onelongitudinal groove in a side wall thereof, whereby protuberances onsaid spline member extend through said screen into said groove toprovide a positive locking action.

5. The invention according to claim 1, said spline member being made ofa material having a relatively high coefficient of surface friction withthe material of said longitudinal channel, whereby said protuberancesact to retain said screen in said channel by frictional engagement.

References Cited in the file of this patent UNITED STATES PATENTS1,135,352 Bunger Apr. 13, 1915 1,697,768 King .Tan. 1, 1929 2,335,361Schiller Nov. 30, 1943 2,639,769 Krantz May 26, 1953 2,797,750 Van DetteJuly 2, 1957 2,835,325 Gilbert et al May 20, 1958

